Drug screening of neuroprotective agents on an organotypic-based model of spinal cord excitotoxic damage.

Purpose: Damage to segmental motoneurons and to spinal cord parenchyma cause denervation atrophy to the muscles, contributing to the chronic disability originated by spinal cord injury (SCI) and spinal motor neuron diseases. After SCI, damage is promoted by several underlying mechanisms, including release of glutamate and consequent over-activation of glutamate receptors, mainly NMDA receptors, that lead to neuronal death. Due to the lack of effective treatments for such conditions, new alternatives need to be explored.

Methods: In order to perform a relatively quick and high-fidelity drug screening, we optimized a postnatal rat organotypic spinal cord culture. By using a glutamate excitotoxic model of spinal cord damage on the explants, we compared the neuroprotective efficacy of four agents: methylprednisolone, erythropoietin, riluzole and rolipram. We evaluated the number of surviving ventral motor neurons stained with the SMI32 antibody and estimated the cord tissue preservation by quantifying the amount of EthD fluorescent probe incorporated into the cells.

Results: The best tissue protection was achieved with riluzole (98%) whereas the highest motoneuron preservation was obtained with methylprednisolone (92%).

Conclusion: The in vitro model used may serve to initiate comparative analyses of new compounds to narrow the choice for future neuroprotective agents to be tested in vivo.